San Francisco is a target of the gun-rights lobby, which, armed with a pair of U.S. Supreme Court rulings, hopes to eliminate gun-control laws passed by cities, counties and states.

The National Rifle Association and a longtime pro-gun lawyer in Sacramento have filed separate lawsuits in federal court that take aim at two San Francisco laws.

One law, approved by the Board of Supervisors in 2007, requires that handguns be kept in locked containers or disabled with a trigger lock.

The other, which has been on the books in various forms since 1994, prohibits the sale of hollow-point bullets and similar ammunition that fragments or explodes upon impact.

The plaintiffs argue that the San Francisco regulations are unconstitutional based on the Second Amendment. They point to the U.S. Supreme Court's Heller decision in 2008 that struck down a Washington, D.C., law and found that people have a constitutional right to keep guns at home for self-defense. Two years later, in the McDonald decision, the high court said that right applies to gun owners in local jurisdictions.

Before the San Francisco cases go to trial in U.S. district court, the city is taking steps to bolster its defense, starting with a vote Thursday at City Hall. The Board of Supervisors' Public Safety Committee recommended amending the laws to add "findings" that explain why city lawmakers believe the regulations make sound public policy.

The findings reference academic studies, public health data, death statistics and similar material. They can be used to show that the laws protect public safety, public health and the public pocketbook as opposed to being a constitutional infringement, said Deputy City Attorney Sherri Kaiser, who is working on the cases.

"There is ample evidence that the two laws are needed now, more than ever, and that they will save countless lives every year," said Supervisor Ross Mirkarimi, chairman of the Public Safety Committee and chief sponsor of the amendments.

The proposed changes, which will be considered by the full board Sept. 27, would "fortify our defense of reasonable gun-safety laws," Mirkarimi added.

But C.D. "Chuck" Michel, the lawyer who sued San Francisco on behalf of the National Rifle Association, said the regulations won't withstand constitutional scrutiny.

"These are the types of regulations that infringe on the Second Amendment's right to keep and bear arms," Michel said in a phone interview from his Southern California office. "What these laws are doing is stopping people from defending themselves adequately."

He estimated that there are more than two dozen substantive lawsuits filed by pro-gun interests across the country to test and expand the Heller and McDonald rulings.

Michel said San Francisco, a city with a long history of valuing personal liberty, "is hypocritical" when it comes to restraints involving guns.

But city officials say the restrictions have and will save lives and taxpayer money. Dr. Randi Smith, a trauma surgeon at the city-run San Francisco General Hospital, testified at Thursday's committee hearing that she has seen firsthand the damage wrought by hollow-point bullets, shredding organs like hamburger meat.

The lone licensed ammo dealer in the city, as a condition for the operating permit, does not sell hollow-point bullets, Kaiser said.

Griffin Dix also showed up City Hall to testify in favor of San Francisco's safe-storage gun law. In 1994, his 15-year-old son, Kenzo, was accidentally shot and killed at a friend's house in Berkeley. The friend found his father's unlocked handgun and, thinking the chamber was empty, pointed the gun at Kenzo and fired the deadly bullet.

"You don't want to get a phone call that says your son has been killed," Dix said.